Reducing hair waving lotion



REDUCING Ham war/mo LorroN John W. Haefele, Mount Healthy,

Procter & Gamble Company, Ohio, a corporation of (ihio No Drawing. Application September 10, 1953, Serial No. 379,461

11 Claims. (Cl. 16787.1)

Ulric, assignor to The Ivorydale, Cincinnati,

The present invention relates to reducing agents for keratin, and more particularly to reducing agents possessing efiective reducing power in prolonged periods of contact with keratin-containing substances without imparting undesirable damage thereto, a characteristic of particular advantage in the treatment of human hair.

Mercaptans are now widely recognized as one of the most useful chemical reagents for softening hair and other keratin-containing substances, certain mercaptans (notably thioglycolic acid) having achieved wide commercial success in cold hair waving procedures. However, these same mercaptans are also used as depilatories and it is ordinarily necessary, therefore, in order to soften a keratin-containing material without irreparably damaging same, to control carefully the period of contact between the mercaptan and the keratinous material being treated.

Thus, in the waving of human hair by means of mercaptan lotions the exercise of precaution in time of contact is particularly important, because, if this time of contact exceeds that necessary to accomplish the desired reduction of the hair, the hair can be rendered harsh and lowered in tensile strength. Since the speed of the reducing reaction between a mercaptan and the keratin of the hair is dependent on so many diverse factors, such as shaft diameter, porosity, chemical composition, and condition of the hair at the time of treatment, i. e. oiliness, etc., it is impossible to generalize as to the correct duration of contact. A given contact time that may be optimum for the hair of one individual may prove detrimental or otherwise unsatisfactory for the hair of another individual due to the tremendous and frequently unaccountable variation in susceptibility to the reducing action of mercaptans which occurs from one person to another. It is an object of this invention to provide mercaptan compositions which are safer to use in reducing keratinous substances than ordinary mercaptan solutions. Another object is to provide reducing compositions which will react with keratin at a satisfactory rate to produce a desired reduced keratin but which will react further to effect damage only at a greatly retarded rate. A further object is to render mercaptans less harsh and damaging to keratin-containing substances without destroying their ability to reduce the keratin sufiiciently to modify the physical form and shape of the substance containing the said keratin. A still further object is to provide improved mercaptan reducing lotions for use in hair waving operations. Another object is to provide a mercaptan reducing agent which may be employed in the treatment of keratin with high degree of safety against damage thus permitting an increase in the period during which the mercaptan reagent may be safely left in contact with desirably reduced keratin and thus minimizing the importance of the variations in the character and reducibility of the hair from one individual to another.

The present invention is based on the discovery that the addition to the mercaptan solutions of the correspond- Patented Get. 4, i955 "ice ing disulfides in certain proportions has the characteristic of retarding the undesirable excessive reaction which usually occurs causing damage to keratin which is overexposed to said mercaptan solutions, without at the same time aifecting unfavorably the desirable reducing reaction I which is necessary to accomplish modification of the keratinous material. The compositions of my invention in aqueous solution under the usual conditions of alkalinity known in the art may thus be efiectively employed to reduce keratin with markedly greater safety against dam age than has normally been possible heretofore. The mercaptans which react in this characteristic manner to the addition of organic disulfide and which come within the scope of my invention are the water-soluble hydroxyand/or alkoxy-substituted non-tertiary mercaptans of the general formula,

where Q represents a radical selected from the group consisting of hydroxy (-OH) and lower alkoxy (--OR where R is an unsubstituted alkyl group of from 1 to 3 carbon atoms in length) and D represents an alkylene radical containing at least 2 carbon atoms and composed exclusively of carbon and hydrogen atoms except for the presence of from O to 4 functional groups each of which is chosen from the class consisting of mercapto (SH), hydroxy (OH) and lower alkoxy (-OR where R is an unsubstituted alkyl group of from 1 to 3 carbon atoms in length). Included within this class of mercaptans are the following: Mercaptoethanol HS-CH --CH -OH 3-mercaptopropanol HSCH2-CH2CH2OH and its position isomer, Z-mercaptopropanol; Thioglycerol HsoH-J -(JH20H OH 1,2-dithioglycerol HS-CHg-CHOH-CHOH-CHSH-CHOH-CH -OH and its position isomers; Thiotetraethylene glycol HSCH CH (OCH -CH -OH and other water-soluble homologues of these. For reasons of economy, mercaptans with molecular weights of over 500, even if watersoluble, are generally not preferred in the practice of this invention.

The organic disulfides, which are capable of producing such outstanding protective qualities when added to solutions containing mercaptans of the above defined class are the corresponding water-soluble non-tertiary disulfides of the same non-tertiary mercaptans and conform to the general formula where Q and Q", like Q above, each represents a radical selected from the group consisting of hydroxy (OH) and lower alkoxy (OR where R is an unsubstituted alkyl group of from 1 to 3 carbon atoms in length) and D' and D", like D above, each represents an alkylene radical containing atleast 2 carbon atoms and composed exclusively of carbon and hydrogen atoms except for the presence of from to 4 functional groups each of which is chosen from the class consisting of mercapto SH), hydroxy (--OI-I) and lower alkoxy (OR where R is an unsubstituted alkyl group of from 1' to 3 carbon atoms in length). By non-tertiary mercaptans and disulfides, I mean, of course, compounds in which each-mercaptoor disulfide-group is attached to a primary or secondary carbon atom rather than to a tertiary carbon atom. It is preferable that all functional groups, i; e. the hydroxy (--OH) and lower alkoxy (OR) as well as the mercapto (-SH) and disulfide (SS) groups be attached to non-tertiary carbon atoms in the compounds of this invention.

Those compositions are particularly preferred in which the alkylene radicals in both the mercaptan and the organic disulfide are all short chain radicals, i. e.,, in the general formulae given above, each of the radicals D, D andD contains from 2 to 6 carbon atoms in the alkylene chain, which does not include any alkoxy groups which may be substituted on the alkylene chain. When each of 'the alkylene radicals D, D' and D is composed exclusiv ely ofcarbon and hydrogen atoms, the number of functional groups present in each being zero, then it is preferred that the said radicals D, D and D" each contam from 2 to 3 carbon atoms because the presence of unsubstituted alkylene radicals containing more than 3 carbon atoms tends to detract from the water-solubility of the compound. However, there does not appear to be any critical upper limit on the chain length of the alkylene radicals D, D and D" so long as the resultant compound is water-soluble.

The following example indicates the effect ofadded disulfide in reducing damage caused by the mercaptan lotion.

Example I.-A strand of 12 individual human hairs was wound on a mandrel having a diameter of 6.5 mm. and then immersed ina solution ammoniacal to a pH of about 9.3 and containing 5.9% thioglycerol; but a, neglir grble amount. of. organic disulfide. After 40 minutes: in this solution at a temperature of 100 F., the strand was rinsed in water, treated with an oxidant fixative solution, and then rinsed in water again. The waved strand was then unwound, measured and an indication of the strength of" the wet hair determined on the Scott 1P2 Serigraph machine which is described below. Measurements made with this machine on the hair before and after treatment were used to determine the 20% Index, a factor indicating the-extent of damage, the lower the 20% Index figure the greater the indicated damage.

In the above test the resultant curl had a diameter of 6.5 mm. and showed a 20% Index of 0.41. parative. test on a. curl formed under similar conditions except with the addition of 2.4% dithiodiglycerol to the mercaptan solution, a curl diameter of 6.3 mm. was produced while the 20% Index increased to 0:57. In this solution themolan ratio of dithiodiglycerol to thioglycerol In a comwas about 0221.0, giving a numerical ratio of disulfide groups to mercaptan groups of 02:10. An increase in the dithiodiglycerol content to about 4.7% (numerical disulfide to mercaptan group ratio of about 0.4:l.0) resulted in a further reduction in damage, the 20% Index being about 0.67, and the curl diameter being about 6.8 mm.

Substantially the same results can be obtained if methyl B-mercapto ethyl ether and its disulfide are substituted for the thioglycerol and dithiodiglycerol in the above example.

This same pattern of an increasing degree of protection as the numerical ratio of disulfide groups to mercaptan groups, i. e. the amount of disulfide added to a given mercaptan solution, is increased as has been consistently noted throughout my work. This work has included solutions containing from about 1 to 15% of the mercaptan at pHs from about 7.0 to about 10. It should be noted that, as is the custom with mercaptan solutions, the higher pHs within the above range are generally used in solutions with the lower concentrations of mercaptan and conversely the lower pHs are employed when the concentration of mercaptans tends to lie in the upper part of the above range. This protective action of the added disulfide can be observed at numerical ratios of disulfide to mercaptan groups from about 0.10210 to about l.5:1.0 provided the time of immersion of the hair in the various solutions is sufficient to produce an eifective wave i. e. generally at least 5 minutes. It should be pointed out that, due to the large difference in the relative quantities of waving solution in contact with the hair when a test curl is immersed in a test tube of solution and when the solution is simply applied to the hair during on-the-head waving, a time of 5 minutes immersion of the test curl in a test tube procedure is equivalent to an exposure time of about minutes or more in actual application waving on the head.

On October 28, 1952, a patent, U.'*S. 2,615,828 was granted to me on compositions containing mercaptans in admixture with organic thiosulfates. As is pointed out in that patent, the mercaptans and organic thiosulfate interact to form disulfide and inorganic sulfite. The instant' invention, however, contemplates the addition of only the disulfide to the mercaptan solution and these two substances interact only by interchange of organic groups toform another disulfide and another mercaptan, mole for mole. The present compositions are thus differentiated from those of U. S. 2,615,828 by their substantial freedom from inorganic sulfite and organic thiosulfate.

In accordance with myobservations, the addition of the organic disulfide does tend to reduce somewhat the speed with which the hydroxy and/ or alkoxy substituted mercaptans react with the keratin and thereby extends somewhat the contact time necessary for desirable reduction. However, the protective action offered by the disulfide against' damage heretofore experienced in pro-- longed exposure, especially in the novel proportions here-- inafterstated, more than compensates for thelowering of the reactivity between the mercaptan and the unreduced keratin. In other words, with increase in disulfidecon-- tent of the. solution. the safety factor increases more"- rapidly than does the contact time required for adequate reduction. Thus the compositions of my invention can; be. used in hair waving and other keratin treating op'-- eraticns with much greater safety than is normally pos sible due to the protective action imparted to the compositions: bythe-presence of limited amounts of the ore ganic'disulfide modifying'agent. A distinct advantage'is' that with marked reduced danger due to over-exposure, directions for use are more easily standardized, thereby enabling non-professional users, who for some reason cannot select a timeof exposure without some danger of unsatisfactory result, to employ the reducing compositionwithsafety and obtain an acceptable wave with mini- The compositions of my invention para mum: damage.

ticularly those mixtures in which the numerical ratio of disulfide groups to mercaptan groups is above 0.4:1.0, are especially adapted for use in the simplified technique of permanent hair waving commonly known as the "no neutralizer method, in which the wave is allowed to become fixed merely by exposure to the air without the application of any special oxidizing solution.

The efiicacy of compositions of my invention, especially as regards hair waving, cannot be evaluated accurately by damage considerations alone and overall performance is therefore determined by a series of tests involving evaluation of a number of measured characteristics of the treated hair, including curl diameter and curl length, as well as damage.

In the case of curl diameter a strand of 12 human hairs 4.25 inches in length and cemented at each end is wet-wound on a mandrel 6.5 mm. in diameter, then saturated for a given time at 100 F. withthe keratin reducing solution. After the wound strand of hair has been exposed to the solution for the given contact time, the solution is rinsed from the strand which is then treated with a solution of inorganic oxidizing agents for 3 minutes to set or fix the curl. Following application of the fixing agent the hair is again rinsed, removed from the mandrel and, while wet and without assistance from external force, is allowed to assume a circular curl which is measured for average diameter. From the information available, deficiency in tightness or D. I. T. of the curl is determined as follows:

D. I. T.=

diameter of mandrel (mm.)

With all variables except reducing solution held constant, D. I. T. is of course indicative of waving efficiency of the solution. The lower the D. I. T. value, the higher the elfectiveness.

Curl length is an indication of both waving efficiency of the reducing solution and damage suffered by the hair during contact with the solution. When freshly formed curls are suspended by the end and shaken up and down, the elasticity or spring of the formed coil may be observed. The degree of laxity of the spiral coil is indicative of waving efliciency of the solution and the degree of damage effected thereby. Numerical indication of this characteristic is obtained by measuring the curl length. The longer the curl, the greater the damage, assuming of course adequate potential efliciency in the reducing solution.

Damage caused by excessive contact of the hair with the solution is also indicated by a factor termed 20% Index. In the determination of this factor, an apparatus known as the Scott 1P2 Serigraph is used. This instrument is designed to record the stretch of keratincontaining fibers by the application of a uniformly increasing load. The ratio of the load required after treatment of the fibers to the load required before treatment to stretch a wet strand of 12 fibers 20% of the original length is referred to as the 20% Index, the higher the Index, the lower the reduction in fiber strength and hence the lower the damage. The instrument is equipped with two clamps between which the strand of 12 fibers of keratin-containing substance is mounted. The strand is surrounded by a water-saturated wicking arrangement which keeps the hair wet during stretching. One of the clamps is fixed to a bar which inclines at a uniform rate when the machine is in operation, and the other clamp is attached to a Weighted carriage adapted to travel along the bar and away from the first mentioned clamp when the bar is inclined. As the inclination of the bar increases, the stretch load applied by the carriage increases at a uniform rate and the strand of fibers is elongated. The relation between load and elongation is continuously recorded on a chart by a pen fixed to the moving carriage. When the elongation of the strand reaches 20% of the orignal length between the clamps,

the machine is reversed and the bar slowly and uniformly 5 returns to horizontal position. With decrease in load the strand contracts, usually at a rate less than the rate of elongation, thereby forming a hysteresis loop on the chart. The load required to effect 20% stretch can be read from the chart.

The difliculty in making direct comparisons of curls produced under ditferent exposure times is readily evident because in addition to the fixed variables there are a number of measured variables. For example, assume that a given reducing solution produces the following result:

Curl Exposure Time (min.) Length D. I. T. Index From the above table it will be observed that the 6 minute curl has the best length but that the 8 minute curl is tighter and that damage increases steadily with exposure time. It-has heretofore been diflicult to choose from such results an optimum time for a given reducing solution.

In order that a fair evaluation of the overall efficiency of the reducing solution may be determined, a method of weighting the different measurements in order to arrive at a single quantity that permits direct comparison of results of different experiments, and especially of different series of experiments, has been established. Toward this end, the extreme values which are normally encountered in permanent waving studies have been set for the important variables as follows:

Minimum Maximum Curl Length (mm) 100 D. I. 'l 0 100 5 Damage (as 20% Index 1.0 0

Each range is divided into 10 parts and the parts are assigned Partial Curl Values ranging from 1 to 10, the lower partial curl values denoting more desirable 1 D. I. T. values over 100 are, of course, possible and in special cases. it is useful to assign them, but, normally, curls having D. I. T. values over 100 are of no interest.

The curl value is defined as the curl values for length (L), I. T.), and damage (D), to the sum of the partial D. Obviously the best sum of the partial deficiency in tightness (D. so that the curl value is equal curl values for L, D. I. T., and possible curl will have a curl value of 3, and the poorer the curl, the higher the curl value.

When a series of experiments is conducted with a given reducing solution at varying times of contact, it is found that the' curl value graduallydecreases to a minimum and then increases. The. minimum point is usually clearcut, although a: good solution may stay at its minimum curl value over an extended period of time. A curl valueof 8 has been arbitrarily chosen on the basis of pastexperience as the maximum value indicating an acceptable curl achieved by well known and acceptable commercials reducingv solutions.

The minimum curl value attainable is, of course, a measureof the quality of the solution, that is, it measures the-optimum that can be' achieved with that solution.

The time to reach minimum curl value is a measure of the: speed of. the reducing action of the solution weighted with: respect to both damage and waving.

The duration of a given curl value, such as 8 or below, for example, over increasing times of contact is indicative of the effective safety period of the solution. In other. words, the effective safety period is a measure of the length of time during which an acceptable curl may be obtained without danger of objectionable damage.

In the example cited above showing actual determinations for curl length, D. I. T. and 20% Index, the fol lowing partial curl values are noted.

It will be observed that a minimum curl value of 8' was obtained after an exposure time of 7 minutes.

With the above explanations the results obtained with reducing solutions of my invention as set forth in the following examples will be readily understood. It is to be borne in mind, however, that the specific conditions given in the examples, wherein all parts shown are by weight, are merely illustrative of the broader aspects of the invention more fully covered in the appended claims.

Example II.5.9 parts (0.055 mol) of thioglycerol and 2.4 parts (0.011 mol) dithiodiglycerol were mixed with water and concentrated ammonium hydroxide (28% NH3) to bring the total to 100 parts and the pH to 9.3. In this solution the numerical ratio of disulfide groups to mercaptan groups was about 0.2: 1.0. Portions of this solution were used to produce a number of test curls of hair by exposure of. several l2-hair strands from the same head of hair for variable time periods. Partial curl values for length, deficiency in tightness, and damage were determined in accordance with the methods described above. The curl value of the solution of this example reached a minimum of 5 after exposure of the test curl to the solution for 7 minutes and the duration of the time during which a curl value of 8 or less was obtained was. about 58 minutes.

In.v comparison with this performance a corresponding solution at pH about 9.3 and containing about 0.555 mol thiogl ycerol per 100 parts of solution but containing no dithiodiglycerol, when used tocurl switches of the samehair, produced a minimum curl value of 6 after 5 minutes exposure. Moreover, the duration of time of exposure during which curl values of 8 or less were obtained was only- 14 minutes.

Example [IL-An aqueous solution similar to that of Example II but containing a greater proportion. of. dithiodiglycerol was prepared from 5.9 parts (0.055 mol). thioglycerol, 4.7. parts (0.022 mol) dithiodiglycerol and sufiicient water and ammonium hydroxide to bring the total to 100 parts and the pH to 9.3. The numerical ratio of disulfide groups to mercaptan groups in this solution-was about 0.4: 1.0. This solution was tested over a range of exposure times as above described and it was foundthat a minimum curl value of 6 was achieved after 7"minut'es exposure and theduration of time" duringwhich a curl value of 8 or less was obtained was about 26.6-

minutes.

Example lV'.--A-n aqueous solution similar to that of- Examples II and III but containing a greater proportion of disulfide was prepared from 5.9 parts (0.055 mol) thioglycerol, 7.1 parts (0.033 mol) dithiodiglycerol and sufficient water and ammonium hydroxide to bring the total to 100 partsand the pH to-9.3. The numerical ratio of disulfide: groups to mercaptan groups in this solution was about 0;6:l-.0. A minimum curl value of 6 was obtained after 60 minutes exposure to this solutipn. The duration of exposure. during'which a curl value of 8 or less was obtained was about 87 minutes.

Even higher numerical ratios of disulfide groups (a' dithiodiglycerol) to'mercaptan groups (as thioglycerol) than thoseeovered by the above examples were examined for their effect upon waving performance. For example, the efiective safety period for anumerical ratio of about 1.6:1.0 was found to be only about 10 minutes. In this manner it was determined that the effective safety period passed through a maximum-value of about 266 minutes at a numerical ratio of disulfide to mercaptan groups of about 0.4:l-.0, and it was found that compositions cont'aining organic disulfide in amounts greater than 1.5 disulfide groups per mercaptan group failed to produce high quality curls-over any practical range of exposure times.

Other mercaptan-disulfide systems containing compounds within' the above-defined class of hydroxy-substituted mercaptans and disulfides were also investigated including among others mercaptoethanol and its disulfide and hydroxyethyl mercaptoethyl ether and its disulfide. In general, useful and worthwhile improvement in protective action and safety were obtained at all numerical ratios of disulfide to mercaptan groups from about 0.10:1.0 to about 1.5:1.0, the disulfide addition producingthe safe waving action of highest quality at numerical ratios of 0211.0 to 0.7110. Specific examples of the improved performance of additional systems are detailed below.

Example V.--The 20% Index on a strand of hair immersedfor 20 minutes in a solution at pH 9.3 containing'4'.25% mercapto ethanol and substantially free of disulfide'was 0.40. However, treatment of a strand of the same hair for 20'minutes in a solution of the same characterexcept with a 17% content of the disulfide of mercapto ethanol (numerical ratio of disulfide group to mercaptan'group of about 0.2: 1.0) produced a curl with 20% Index of 0.66, the higher value being indicative of the much'l'ess severe damage cause by the latter solution.

Example'Vl.The 20% Index on a 12-strand switch of hair after immersion for 60 minutes in a solution ammoniacal to pH 9.3 and containing 6.6% by weight of hyd'roxyethyl mercaptoethyl ether but no disulfide was only 0;15'. However, treatment of a switch of the same hair for 60 minutes in a solution ammoniacal to the same pH and containing the same concentration of hydroxyethyl mercaptoethyl ether. but containing also the disulfide of said mercaptan in a weight concentration of 2.7% (numerical ratio of disulfide to mercaptan groups of about 0.2:l.0) produced a curl with a 20% Index of 0.41. This increase of'20% Index from 0.15 to 0.41 through the addition of organic disulfide in limited proportions illustrates dramatically how these organic disulfides are able to protect the'hair against damage during extended periods of exposure to hair waving lotions containing mercaptain as the active ingredient.

The compositions. of this invention may be prepared either by dissolving the organic disulfi des in the mercaptan sol'ution'directly or by oxidizing a portion of the mercaptain already in solution to form the disulfide in situ. In

either case, the concentration of the hydroxy and/or alkoxy substituted mercaptan in the active mercaptan fOl'm' Sl'lOHld be at least 1% by weight and, for cold hair waving, preferably in the range of 4to 9% by weight of the finished-solution, although as much as 15% by weight may be useful with certain species, higher molecular weight.

Example VII.0.06 mol of l,2-dithioglycerol is dissolved in about 75 cc. of water, the pH is adjusted to about 8 by the addition of concentrated ammonium hydroxide (28% NH?) and 6.8 grams hydrogen peroxide solution strength) is added, sufficient to oxidize one third of the total mercaptan groups present to disulfide groups. The resulting solution after being adjusted to 100 parts total and a pH of 9.3 by the addition of water and ammonia, contains disulfide groups and mercaptan groups in a numerical ratio of l to 4 or 0.25: 1.0 and shows good quality waving performance with increased hair protection over a similar solution containing 0.04 mol of 1,2-dithioglycerol per 100 grams but no disulfide.

In the art of waving hair wherein compositions of the present invention are particularly useful, it is preferable that the alkalinity be maintained at a pH value between 8.5 and 9.5, but in the treatment of other keratin-containing substances such as wool for the purpose of effecting reduction of keratin, pH values from about 7 to about 10 can be employed, and the protective action of the disultide as exemplified above is clearly evident throughout this entire pH range.

In the above examples the solutions were made alkaline by the addition of ammonia, it being well known that solutions of mercaptans which have been rendered alkaline by the addition of ammonia, are superior, especially for hair waving, to comparable solutions which have been rendered alkaline by the addition of other alkalizing materials such as potassium carbonates and hydroxides. Part of the reason for the superiority of ammonia as an alkalizer resides in the lower destructive action which ammoniacal solutions generally show toward the keratincontaining substance. Therefore, in the practice of the present invention, the advantageous protective action of the disulfide demonstrated above in connection with am- .moniacal solutions is sometimes of slightly greater advantage in the case of solutions rendered alkaline by the addition of alkali metal hydroxides or carbonates or mixtures thereof with ammonia. Other alkalizing agents including water-soluble amines such as ethyl amine, monoethanolamine and morpholine, and also water-soluble quaternary ammonium bases such as tetraethyl ammonium hydroxide can also be used. All of these alkaline agents, and mixtures thereof, may be substituted for the ammonium hydroxide employed in the foregoing examples, in appropriate quantities, with generally comparable results.

While the essential ingredients of the compositions of my invention include one or more of each of the previously defined classes of compounds, namely mercaptans and disulfides, it is to be understood that other ingredients such as perfume, opacifying agents, buffers and other additives designed to impart especially desired qualities to the reducing solution may be incorporated without departing from the spirit of the invention.

The term consisting essentially of is used herein in the definition of the ingredients whose presence in the claimed composition is essential, and as used it is intended to exclude the presence of other materials in such amounts as to interfere substantially with the properties and characteristics possessed by the composition set forth but to permit the presence of other materials in such amounts as not substantially to affect said properties and characteristics adversely.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A hair Waving lotion for effectively waving hair without imparting undesirable damage thereto even in prolonged periods of contact, consisting essentially of a mixture in aqueous solution of water-soluble non-tertiary mercaptan of the general formula,

especially those of and water-soluble, non-tertiary, organic disulfide of the general formula,

Q'DI S S DII QPI where Q, Q and Q" each represents a radical selected from the group consisting of hydroxy (OH) and lower alkoxy (OR where R is an unsubstituted alkyl group of from 1 to 3 carbon atoms in length) and D, D and D" each represents an alkylene radical'containing at least 2 carbon atoms and composed exclusively of carbon and hydrogen atoms except for the presence of from O to 4 functional groups each of which is chosen from the class consisting of mercapto (SH), hydroxy (OH) and lower alkoxy (OR where R is an unsubstituted alkyl group of from 1 to 3 carbon atoms in length), the amount of said mercaptan being from about 1 to about 15% by weight of the solution, the numerical ratio of organic disulfide groups to mercapto groups in solution being from about 0.10:1.0 to about 1.5 :1.0, the pH of the solution being from about 8.5 to about 9.5, and the solution being substantially free from both sulfite and organic thiosulfate.

2. A hair Waving lotion as in claim 1 in which each of the radicals D, D and D" contains from 2 to 6 carbon atoms in the alkylene chain exclusive of any carbon atoms present in any alkoxy groups substituted on the alkylene chain.

3. A hair waving lotion as in claim 1 in which each of the radicals D, D and D" is composed exclusively of carbon and hydrogen atoms and contains from 2 to 3 carbon atoms.

4. A hair waving lotion as in claim 1 in which the lotion is ammoniacal to a pH from about 8.5 to about 9.5.

5. A hair waving lotion as in claim 4 in which the amount of mercaptan is from about 1 to about 9% by weight and the numerical ratio of organic disulfide groups to mercaptan groups is between about 02:l.0 and about 0.7: 1.0.

6. A hair waving lotion for effectively waving hair without imparting undesirable damage thereto even in prolonged periods of contact, consisting essentially of a mixture in aqueous solution of water-soluble, hydroxysubstituted, non-tertiary mercaptan of the general formula,

HS-D-OI-I and water-soluble, non-tertiary, organic disulfide of the general formula,

where D, D and D" each represents an alkylene radical containing at least 2 carbon atoms and composed exclusively of carbon and hydrogen atoms except for the presence of from 0 to 4 functional groups each of which is chosen from the class consisting of mercapto (4H), hydroxy (-OH) and, lower alkoxy (OR where R is an unsubstituted alkyl group of from 1 to 3 carbon atoms in length), the amount of said hydroxy-substituted mercaptan being from about 1 to about 15 by weight of the solution, the numerical ratio of organic disulfide groups to mercapto groups in solution being from about 0.10:1.0 to about 1.5:l.0, the pH of the solution being from about 8.5 to about 9.5, and the solution being substantially free from both sulfite and organic thiosulfate.

7. A hair waving lotion as in claim 6 in which the hydroxy-substituted mercaptan is thioglycerol and the organic disulfide is dithiodiglycerol.

8. The hair waving lotion of claim 6 in which the hydroxy-substituted mercaptan is mercapto-ethanol and the organic disulfide is diethanol disulfide.

9. A hair waving lotion for effectively waving hair without imparting undesirable damage thereto even in prolonged periods of contact, consisting essentially of a mixture in aqueous solution of water-soluble, lower alkoxy-substituted, non-tertiary mercaptan of the general formula,

HS-D-OR 1'1 and water-soluble", nomtertiary, organic disulfide of the: general formula,

ofsaid lower alkoxy-substitutedmercaptan being from;

about 1: to about. 15% by weight of the solution, the numerical ratio of organic disulfide groups tomercapto groups in solution beingfrom about 0.10:1.0 to about l'-.5z1 .0,. the pH of the solution being. from about 8.5 toqabout 9.5, and: the solution being substantially free from both sulfite. andorganic thiosulfate.

, 10. A- hair waving: lotion as in claim 9 in which the amount of lower alkoxysubstituted mercaptan is from about 4% to about 9% by weight and'the numerical ratio 12 of. organic disulfide groups to mercaptan groups" is between about 0.2:1.0 and about O.7:1.0.

11. The hair waving lotion of claim 9 in which the lower alkoxy-substituted mercaptan is methyl B-mercapto- 5 ethyl ether and the organic disulfide is di-(rnethoxyethyl)' References Cited in the file of this patent UNITED STATES PATENTS McDonough Dec. 4, 1951 2,615,782 Haefele Oct. 28, 1952' 2,615,783 Haefele Oct. 28, 1952' OTHER REFERENCES Morelle, Derniers progres de la chimie de londulation permanente, La Parfumerie Moderne, 1951, pp. 64-74,v

especially at p. 69.

Draize et al., Percutaneous Toxicity of Thioglyco- 20 lates, Proc. Toilet Goods Assn., May 16, 1947, pp.

29-31, esp. at p. 30, column 1.

Dahle et al., Methods Analyzing Cold Wave Solutions, Am. Perfumer, Feb. 1945, pp. 35-38. 

1. A HAIR WAVING LOTION FOR EFFECTIVELY WAVING HAIR WITHOUT IMPARTING UNDERSIRABLE DAMAGE THERETO EVEN IN PROLONGED PERIODS OF CONTACT, CONSISTING ESSENTIALLY OF A MIXTURE IN AQUEOUS SOLUTION OF WATER-SOLUBLE NON-TERTIARY MERCAPTAN OF THE GENERAL FORMULA, 